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为适应智能变电站全数字化保护系统对相量提取算法的新要求,针对短窗算法滤波性能差而傅里叶算法延时较长且数据窗固定的不足,提出了一种窄带滤波器与变长数据窗相结合的相量提取算法。首先采用窄带滤波器对采样值序列进行带通滤波,并由短窗算法估算滤波器初值,以减小窄带滤波器暂态过程影响,缩短滤波器延时。然后对滤波器输出序列采用基于最小二乘法的变数据窗算法,最终准确提取相量特征。算法充分考虑了智能变电站的特点,实现了可变数据窗的相量提取,在保证滤波精度的同时提高了相量提取速度。数字仿真和动模数据验证表明,该算法可在发生故障后较短时间内准确提取出基波相量,有效提高了智能变电站全数字化保护的速动性和适应性。
In order to meet the new requirements of phasor extraction algorithm in intelligent substation digital protection system, aiming at the shortcoming of short window algorithm and the short delay of Fourier algorithm and the fixed data window, a narrow band filter with variable length Data Window Combining Phasor Extraction Algorithm. Firstly, a narrow-band filter is used to band-pass the sample sequence and the initial value of the filter is estimated by the short-window algorithm to reduce the influence of the transient process of the narrowband filter and shorten the delay of the filter. Then the filter output sequence based on the least squares method of variable data window algorithm, the final accurate extraction of phasor characteristics. The algorithm takes full account of the characteristics of the intelligent substation and realizes the phasor extraction of the variable data window, which improves the extraction speed of the phasor while ensuring the filtering accuracy. Simulation results of digital simulation and dynamic model show that the algorithm can accurately extract the fundamental phasor in a short time after the failure, effectively improving the speed and adaptability of intelligent digital substation protection.